SDL2 seems utterly broken on Windows

[sheaf]

I was using the SDL package just fine on Windows about a year ago. Since then, it seems things have changed and I have not managed to get SDL2 working at all.

On GHC 9.12 and below, when trying to build sdl2 I get errors like:

error: ld.lld: warning: ignoring unknown argument: -exclude-symbols:console_ansi_main
ld.lld: warning: ignoring unknown argument: -exclude-symbols:console_wmain
ld.lld: warning: ignoring unknown argument: -exclude-symbols:WinMain
ld.lld: error: -exclude-symbols:console_ansi_main is not allowed in .drectve
ld.lld: error: -exclude-symbols:console_wmain is not allowed in .drectve
ld.lld: error: -exclude-symbols:WinMain is not allowed in .drectve
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I think this is because the version of Clang shipped with GHC 9.12 is too old, so that's not a problem with the sdl2 package.

Now, GHC 9.14 has updated the version of Clang and includes many other Windows-related fixes, so I was hopeful. Indeed, the bug above seems to have gone away. However, the following simple program:

main :: IO ()
main = do
  putStrLn "Hello"
  getLine
  putStrLn "Goodbye"

seems to run into issues when compiling with a dependency on sdl2. When I run the program, I get:

<stdin>: hGetLine: invalid argument (Bad file descriptor)
While handling GHC.Internal.IO.FD.fdRead: invalid argument (Bad file descriptor)

This is with a trivial cabal package with build-depends: base, sdl2 == 2.5.5.0 (sdl2-2.5.5.1 doesn't seem to compile, but that's a separate issue that I've fixed in #321). Removing the dependency on sdl2 makes it all work fine.

I'm using the mingw-w64-clang-x86_64-SDL2-2.32.10-1 system library, if that makes a difference.

I've opened an issue on the GHC issue tracker as well.

[AndreasPK]

I've looked at this and the issue with 9.14 doesn't seem to be an issue in GHC. Rather sdl "steals" the standard file descriptors by default which seems to cause some weirdness.